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standby links. User traffic travels over the active link to the master NPE1, and NPE1 forwards
user traffic to the Internet.
If a VRRP-disabled interface tracked by NPE1 fails or the active link to NPE1 fails, NPE1
reduces its VRRP priority and enters the Backup state. The priority reduction triggers a master/
backup VRRP switchover. After that, user traffic switches to the standby link. After the fault is
removed, the tracked interface or active link goes Up, and NPE1 increases its VRRP priority.
Although NPE1 increases its VRRP priority to be higher than that of the existing master NPE2,
NPE1 can switch to the Master state only after receiving VRRP packets sent by NPE2, delaying
the master/backup VRRP switchback. If the active/standby link switchback is complete earlier
than the master/backup VRRP switchback, user-to-network traffic is dropped. The rapid VRRP
switchback function can be used to prevent traffic loss.
The rapid VRRP switchback function allows the recovered master device to preempt the Master
state without waiting for VRRP packets sent by the existing master device.
Figure 4-13
Networking diagram for the rapid VRRP switchback function
PE1
NPE1
PE2
NPE2
UPE
User
network
Internet
Active
link
Standby
link
VRRP
Master
Backup
PE1
NPE1
PE2
NPE2
UPE
User
network
Internet
Active
link
VRRP
Master
Backup
Data flow
Standby
link
NOTE
The rapid VRRP switchback function currently takes effect only on the master device in an mVRRP backup
group in a situation where the master device tracks a VRRP-disabled interface or feature and reduces its
priority if the tracked interface or feature status changes.
Perform the following steps on the master device in an mVRRP backup group:
HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability
4 VRRP Configuration
Issue 02 (2014-09-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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